This islet cell antibody (ICA) test is useful in predicting the development of Type I diabetes and has potential relevance in monitoring future measures of prevention and treatment. However, problems with standardization limit the reliability and availability of the ICA assay. The goal of this work is to produce a standardized and hence more reliable system for detecting ICA through the innovative use of integrated "Standardization" and "Test" Kits. The Phase II objectives are to determine the predictive value of the ICA test reagents developed in Phase I, develop ICA kits with them and evaluate the performance of these kits for use in Phase III. The test system will be evaluated as follows: Type II diabetics and first degree relatives of Type I diabetics having ICA in this test system will be followed for the development of Type I diabetes, the latter by intravenous glucose tolerance and insulin response testing. Prototype kits will be field tested with known positive and "unknown" specimens to evaluate performance in terms of specificity, sensitivity and intra- and interlaboratory reproducibility. The research will bring the ICA test system to the point of marketing for research use and application for approval for diagnostic use.